Medical Marijuana Laws May Lead to Fewer Traffic Deaths

Research over the years has highlighted a number of public policies that have proven effective at reducing traffic fatalities. Increasing the drinking age to 21 reduced deaths by about 9 percent. And mandatory seat belt laws have had a similar impact in saving the lives of 14-to-18-year-olds.

Policy-makers may now want to add to this list an unexpected intervention: Legalize medical marijuana.

Economists D. Mark Anderson and Daniel I. Rees have published a new paper finding that traffic fatalities fell by nearly 9 percent in the 13 states that legalized medical marijuana between 1990 and 2009. The two data points – traffic deaths and marijuana legalization – don’t seem obviously connected. But Anderson and Rees point out that they’re both linked to a common social ill: beer consumption.

Ample data has pegged drunken drivers as responsible for a disproportionate share of deadly traffic accidents. And the researchers uncover data showing that beer consumption falls when marijuana is legalized, suggesting that some people may be substituting one substance for the other once pot is more readily – and acceptably – available.

Anderson and Rees relied on state-level traffic data from the National Highway Traffic Safety Administration, as well as on data from the Beer Institute (which is, in fact, a real thing) revealing a 5.3 percent drop in beer sales associated with marijuana legalization. (Beer is also, the researchers point out, the most popular alcoholic drink among 18-to-29-year-olds.)

Anderson and Rees don’t push any policy prescriptions, although they hint that these findings – the first of their kind – should inform the debate around medical marijuana, which more often revolves around weak concerns that medical pot will criminalize kids and boost recreational use. They do note that legalization is associated with increased use of marijuana among adults, but not among minors.

They also conclude the study with a cautionary note: This research doesn’t mean smoking pot will make you a safer driver than your drunk-driving friends. One of the likely explanations behind these findings is that people who smoke are more likely to do so in private, while people who drink are socially accepted in bars – and may very well drive to get there.

People who rely on medical marijuana laws, in other words, may be substituting beer for pot, but also the neighborhood bar for their basement. Conclude the authors:

If marijuana consumption typically takes place at home, then designating a driver for the trip back from a restaurant or bar becomes unnecessary, and legalization could reduce traffic fatalities even if driving under the influence of marijuana is every bit as dangerous as driving under the influence of alcohol.

About the Author

Emily Badger is a former staff writer at CityLab. Her work has previously appeared in Pacific Standard, GOOD, The Christian Science Monitor, and The New York Times. She lives in the Washington, D.C. area.